feat: Add a foundational set of BMM, BMB, TEA, and Core workflows, agent definitions, and supporting templates.

_bmad/tea/workflows/testarch/atdd/instructions.md

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+<!-- Powered by BMAD-CORE™ -->
+
+# Acceptance Test-Driven Development (ATDD)
+
+**Workflow ID**: `_bmad/tea/testarch/atdd`
+**Version**: 5.0 (Step-File Architecture)
+
+---
+
+## Overview
+
+Generates **failing acceptance tests** before implementation (TDD red phase), plus an implementation checklist. Produces tests at appropriate levels (E2E/API/Component) with supporting fixtures and helpers.
+
+---
+
+## WORKFLOW ARCHITECTURE
+
+This workflow uses **step-file architecture**:
+
+- **Micro-file Design**: Each step is self-contained
+- **JIT Loading**: Only the current step file is in memory
+- **Sequential Enforcement**: Execute steps in order without skipping
+
+---
+
+## INITIALIZATION SEQUENCE
+
+### 1. Configuration Loading
+
+From `workflow.yaml`, resolve:
+
+- `config_source`, `test_artifacts`, `user_name`, `communication_language`, `document_output_language`, `date`
+- `test_dir`
+
+### 2. First Step
+
+Load, read completely, and execute:
+`{project-root}/_bmad/tea/workflows/testarch/atdd/steps-c/step-01-preflight-and-context.md`
+
+### 3. Resume Support
+
+If the user selects **Resume** mode, load, read completely, and execute:
+`{project-root}/_bmad/tea/workflows/testarch/atdd/steps-c/step-01b-resume.md`
+
+This checks the output document for progress tracking frontmatter and routes to the next incomplete step.